ABSTRACT
The case of a 40-year-old man who sustained a medial malleolar fracture with extension of the fracture into the tibial plafond is discussed. Before surgery, the physical examination revealed an Achilles tendon rupture. Surgical treatment to repair the bone and tendon injury was performed. Achilles tendon rupture is not an uncommon injury, but it is rarely associated with a fracture. When a fracture is present, the Achilles tendon injury can be overlooked, which may result in a delay of treatment or residual morbidity.
Subject(s)
Achilles Tendon/injuries , Ankle Injuries/complications , Fractures, Comminuted/complications , Tibial Fractures/complications , Achilles Tendon/surgery , Adult , Ankle Injuries/diagnosis , Ankle Injuries/diagnostic imaging , Ankle Injuries/surgery , Casts, Surgical , Follow-Up Studies , Fracture Fixation, Internal , Fractures, Comminuted/diagnostic imaging , Fractures, Comminuted/surgery , Humans , Magnetic Resonance Imaging , Male , Rupture , Tibial Fractures/diagnostic imaging , Tibial Fractures/surgery , Time Factors , Tomography, X-Ray ComputedABSTRACT
This article reports the cases of what we believe to be the youngest patients with traumatic meniscal tears treated by repair. The 2 cases were treated with different meniscal repair techniques. A review of the literature regarding traumatic meniscal tears in children is provided.
Subject(s)
Arthroscopy/methods , Knee Injuries/surgery , Menisci, Tibial/surgery , Suture Techniques , Child, Preschool , Female , Humans , Knee Injuries/diagnosis , Knee Injuries/physiopathology , Magnetic Resonance Imaging , Male , Menisci, Tibial/pathology , Range of Motion, Articular , Rupture , Tibial Meniscus InjuriesABSTRACT
Augmentation is a well-accepted and common component of coracoclavicular ligament repairs and reconstructions. The purpose of this study was to examine and compare the strength, stiffness, and mode of failure of the coracoclavicular ligament complex and four different augmentation techniques in cadaveric shoulders. There was no significant difference in the mean failure load between the intact ligament complex (724.9+/-230.9 N) and augmentations performed with braided polydioxanone (PDS) (676.7+/-115.4 N) or braided polyethylene placed through (986.1+/-391.1 N) or around (762.7+/-218.2 N) the clavicle. The mean failure load for augmentations using a 6.5-mm cancellous screw through the clavicle and into a single cortex of the coracoid (390.1+/-253.6 N) was significantly lower than that for the intact coracoclavicular ligaments. There was no difference in mean stiffness between the intact coracoclavicular ligament complex (115.9+/-36.2 N/mm) and the braided polyethylene augmentations placed through (99.8+/-22.2 N/mm) or around (90.0+/-25.5 N/mm) the clavicle. Polydioxanone augmentations were significantly less stiff (27.4+/-3.3 N/mm) than the intact complex, while screw augmentations were significantly stiffer (250.4+/-88.2 N/mm). There were no significant differences in strength or stiffness of braided polyethylene reconstructions placed around or through a drill hole in the clavicle.
Subject(s)
Acromioclavicular Joint/physiology , Acromioclavicular Joint/surgery , Arthroplasty/methods , Ligaments, Articular/physiology , Ligaments, Articular/surgery , Adult , Analysis of Variance , Biomechanical Phenomena , Cadaver , Humans , Stress, MechanicalABSTRACT
We reviewed the results in 13 patients who underwent simultaneous allograft reconstruction of both the anterior and posterior cruciate ligaments after a knee dislocation (nine acute and four chronic injuries). Seven patients sustained related medial collateral ligament injuries and six patients had posterolateral complex injuries. Ligament reconstructions were performed using fresh-frozen Achilles or patellar tendon allografts. At follow-up evaluation (mean of 38 months), only one patient described the reconstructed knee as normal. Six patients had returned to unrestricted sports activities and four had returned to modified sports. The average extension loss was 3 degrees (range, 0 degree to 10 degrees) and average flexion loss was 5 degrees (range, 0 degree to 15 degrees). The KT-1000 arthrometer measurements at 133 N anterior-posterior tibial load showed a mean side-to-side difference of 4.5 mm (range, 0 to 10) at 20 degrees and 5.0 mm (range, 0 to 9) at 70 degrees. The mean Lysholm score was 88 (range, 42 to 100). International Knee Documentation Committee ratings were six nearly normal, five abnormal, and one grossly abnormal. Two patients required manipulations for knee stiffness. This study demonstrates that reconstruction of both cruciate ligaments can restore stability sufficient to allow sports activity in most patients with knee dislocations, but "normal" results are difficult to achieve.
Subject(s)
Anterior Cruciate Ligament/surgery , Joint Dislocations/surgery , Knee Injuries/surgery , Posterior Cruciate Ligament/surgery , Tendons/transplantation , Adolescent , Adult , Anterior Cruciate Ligament Injuries , Cryopreservation , Humans , Middle Aged , Posterior Cruciate Ligament/injuries , Treatment OutcomeABSTRACT
Three cases of Staphylococcus epidermidis septic arthritis following inside-out arthroscopic meniscus repair within a 4-day period at the same facility are described. All three patients responded to surgical debridement and 4 to 6 weeks of intravenous antibiotics. In each instance, the meniscus and repair sutures were left intact; 12- to 38-month follow-up revealed no evidence of infection or meniscal symptoms. Epidemiological investigation implicated the meniscus repair cannulas as one of the few factors common to all three cases. Molecular typing of bacterial DNA revealed that two of the three isolated organisms showed identical pulsed-field gel electrophoretic patterns, implying a common source of inoculation. Experimental contamination of the cannulas revealed that only sterilization involving ultrasonification, lumen washing by water jet, and steam sterilization resulted in clean and sterile cannulas.
Subject(s)
Arthritis, Infectious/etiology , Endoscopy/adverse effects , Knee Injuries/surgery , Menisci, Tibial/surgery , Sepsis/etiology , Staphylococcal Infections/microbiology , Surgical Wound Infection/etiology , Adult , Anti-Bacterial Agents , Arthritis, Infectious/drug therapy , Arthritis, Infectious/surgery , Arthroscopes , Arthroscopy/adverse effects , DNA, Bacterial/analysis , Debridement , Drug Therapy, Combination/therapeutic use , Endoscopes , Equipment Contamination , Follow-Up Studies , Humans , Male , Reoperation , Sepsis/drug therapy , Sepsis/surgery , Staphylococcal Infections/drug therapy , Staphylococcal Infections/surgery , Staphylococcus epidermidis/genetics , Staphylococcus epidermidis/isolation & purification , Surgical Wound Infection/drug therapy , Surgical Wound Infection/surgery , Synovial Fluid/microbiology , Tibial Meniscus InjuriesABSTRACT
This article characterizes chondral injuries and reviews the results of microfracture treatment in high-level competitive and recreational athletes. Thirty-eight high-level and 140 recreational athletes completed functional questionnaires preoperatively and yearly postoperatively, recording symptoms, function, and activity level. Second-look arthroscopy tapes were available in 26 high-level and 54 recreational athletes. The mean follow-up for the high-level athletes was 3.7 +/- 1.4 years. Chondral defects averaged 223 +/- 180 mm2. Lesion size and follow-up were not significantly different in the recreational group. Functional questionnaire responses demonstrated significant improvements from the time of microfracture to final follow-up. Improvement in function and symptoms was similar for the competitive and recreational athletes.
Subject(s)
Athletic Injuries/therapy , Cartilage, Articular/injuries , Adolescent , Adult , Anterior Cruciate Ligament Injuries , Female , Humans , Knee Injuries/therapy , Male , Treatment OutcomeABSTRACT
Glenohumeral translation and rotation were measured in 6 grossly normal, fresh frozen shoulder preparations while a manual load was applied to the humerus. The same tests (maximum elevation, total rotation, anterior/posterior (A/P) translation, and inferior translation) were repeated for each shoulder through 8 series: 1 with the shoulder intact, 1 with the shoulder vented, and 6 with progressively larger humeral head components after hemiarthroplasty. There was an inverse linear relation between humeral head component size and all 4 outcome variables. Replacing the native head with a component of equal diameter reduced elevation 20%, rotation 40%, A/P translation 50%, and inferior translation 60% in the vented shoulder. Replacing the native head with a component of equal effective volume decreased elevation 8%, rotation 20%, A/P translation 25%, and inferior translation 40% in the vented shoulder. Increasing humeral head component size decreased rotation, A/P translation, and inferior translation by similar percentages and elevation somewhat less. Humeral head component size is better described in terms of volume than in terms of diameter or offset.
Subject(s)
Arthroplasty, Replacement , Humerus/surgery , Range of Motion, Articular , Shoulder Joint/physiology , Shoulder Joint/surgery , Cadaver , Humans , Osteotomy , RotationABSTRACT
The rotator cuff is the primary dynamic stabiliser of the glenohumeral joint and is placed under significant stress during overhead and contact sports. Mechanisms of injury include repetitive microtrauma, usually seen in the athlete involved in overhand sports, and macrotrauma associated with contact sports. Rotator cuff injury and dysfunction in the overhand athlete may be classified based on aetiology as primary impingement, primary tensile overload, and secondary impingement and tensile overload resulting from glenohumeral instability. A thorough history and physical examination are paramount in the evaluation, classification and treatment planning of the athlete with rotator cuff pathology. Imaging studies are a helpful adjunct to the history and physical. Athletes with primary impingement are usually middle aged or older and often have chronic shoulder pain and sometimes weakness associated with overhand sporting activities. Night pain is typical of full thickness rotator cuff tears. Impingement signs are positive and strength of elevation and external rotation are often limited. They usually respond to a nonoperative rehabilitation programme centred on decreasing inflammation, restoring range of motion and strengthening the rotator cuff and scapular stabilisers. Depending on the degree of cuff pathology, acromioplasty, debridement of partial cuff tears, and repair of full thickness tears are usually successful in those who fail a rehabilitation programme. Overhand athletes with cuff pathology secondary to subtle anterior instability are usually young and complain of pain and decreased throwing velocity. Instability may be so subtle that it is only detectable through a positive relocation test on examination. The majority of these athletes do not have a Bankart lesion on magnetic resonance imaging or arthroscopic examination. Arthroscopic examination usually demonstrates anterior capsular laxity (positive 'drive-through' sign), as well as superior-posterior labral and cuff injury typical of internal impingement. If rehabilitation alone is not successful, a capsulolabral repair followed by rehabilitation may allow the athlete to return to their previous level of competition. The athlete with an acute episode of macrotrauma to the shoulder resulting in cuff pathology usually presents with pain, limited active elevation and a positive 'shrug sign'. Arthroscopy and debridement of thickened, inflamed or scarred subacromial bursa with cuff repair or debridement as indicated is usually successful in those who do not respond to a rehabilitation programme.
Subject(s)
Athletic Injuries/etiology , Rotator Cuff Injuries , Arthroscopy , Athletic Injuries/classification , Athletic Injuries/rehabilitation , Athletic Injuries/surgery , Cumulative Trauma Disorders/etiology , Diagnostic Imaging , Humans , Joint Instability/complications , Medical History Taking , Middle Aged , Muscle Weakness/etiology , Patient Care Planning , Physical Examination , Physical Therapy Modalities , Range of Motion, Articular , Rotation , Rotator Cuff/anatomy & histology , Rotator Cuff/physiology , Rotator Cuff/surgery , Rupture , Shoulder Impingement Syndrome/etiology , Shoulder Joint/anatomy & histology , Shoulder Joint/physiology , Stress, Mechanical , Tensile StrengthABSTRACT
In vivo dissociation of the Morse-taper of shoulder arthroplasty modular humeral components has been reported. The incidence of this complication appears to be approximately 1:1000. The objective of this study was to identify conditions that might affect the Morse-taper interface strength in humeral components. Mechanical tests were performed to load and dissociate humeral heads from the humeral stems (titanium). The effect of loading rate, load amplitude, and number of impactions was investigated. Dissociation force was measured after the taper was contaminated with water, oil, blood, and bone cement particles. The mean dissociation force after two impactions with a mallet was 2926 +/- 955 N. Dissociation force was linearly proportional to impaction force. Repetitive loading beyond two impactions did not significantly increase taper strength. Contamination of the taper with as little as 0.4 ml of fluid could prevent fixation of the taper.
Subject(s)
Joint Prosthesis/adverse effects , Shoulder Joint/surgery , Biomechanical Phenomena , Equipment Failure , Humans , Humerus , Materials TestingABSTRACT
Tendons are complex composite material composed primarily of water, collagen, proteolycans, and cells, designed to transmit tensile loads from muscle to bone. Although rotator cuff tendons differ in many ways from other tendons in the body, a knowledge of basic tendon structure and function is helpful in understanding rotator cuff tendon biology, injury, and repair. In addition to type I collagen, rotator cuff tendons contain small amounts of type III collagen, which play a role in healing and repair. In comparison with other tendons, the increased glycosaminoglycan and proteoglycan content seen in rotator cuff tendons may be adaptive, pathologic, or both. The etiology of rotator cuff pathology is probably related to trauma, aging, and degeneration. As our understanding of these processes increases, we will be able to develop and implement improved preventative and therapeutic interventions for rotator cuff pathology.
Subject(s)
Rotator Cuff/anatomy & histology , Animals , Collagen/chemistry , Fibroblasts , Glycosaminoglycans/analysis , Humans , Proteoglycans/analysis , Rotator Cuff/chemistry , Rotator Cuff/physiology , Rotator Cuff InjuriesABSTRACT
Rotator cuff and biceps tendons that appeared grossly normal were procured from adult cadavers without a history of shoulder problems. These tendons were analyzed for the amount and type of glycosaminoglycan, type of proteoglycan, and histology. When compared with the distal/tensional region of biceps tendon, the glycosaminoglycan content of supraspinatus, infraspinatus, and subscapularis tendons was 2.5-fold higher and the glycosaminoglycan content of the proximal/compressed region of biceps tendon was 3-fold higher. The ratio of hyaluronic acid to chondroitin sulfate/dermatan sulfate in all three cuff tendons was approximately 1. Rotator cuff tendons contained large proteoglycan similar to aggrecan, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel migration elution from Sepharose CL-4B, and content of both chondroitin sulfate and keratan sulfate chains. Both decorin and biglycan were also present, as demonstrated by migration in sodium dodecyl sulfate-polyacrylamide gels and core protein immunoreactivity. In contrast decorin was the only proteoglycan prominent in distal/tensional regions of biceps tendon. Histological analysis showed layers of loosely organized alcian blue-stained material running between the longitudinal collagen fiber bundles. The proteoglycan content of rotator cuff tendons was similar to fibrocartilage in tendons that have been subjected to compressive loads in situ. This suggests that cells of normal adult rotator cuff tendons have adapted to loads distinct from pure tension. However, the histological organization did not resemble mature fibrocartilage. The increased amount of proteoglycan in rotator cuff tendons may serve to separate and lubricate collagen bundles as they move relative to each other during normal shoulder motion.
Subject(s)
Extracellular Matrix Proteins , Proteoglycans/analysis , Rotator Cuff/chemistry , Adult , Aged , Antibody Specificity , Blotting, Western , Carrier Proteins/immunology , Carrier Proteins/metabolism , Cartilage/chemistry , Cartilage/enzymology , Chondroitin Lyases/metabolism , Chromatography, Gel , Electrophoresis, Polyacrylamide Gel , Fibromodulin , Humans , Hyaluronic Acid/analysis , Middle Aged , Proteoglycans/immunology , Rotator Cuff InjuriesABSTRACT
The causes and incidence of rotator cuff injuries in patients under the age of 40 has not been clearly established. The present study focuses on a group of 10 male contact athletes with rotator cuff injuries related to trauma sustained during football (ages from 24 to 36 years). Symptoms included pain and dysfunction in all 10 patients and a positive shrug sign in 8 of 10. The diagnoses for these patients were two isolated contusions, five partial-thickness tears, and three full-thickness tears. Surgery was performed on all patients after nonoperative treatment failed. Three partial-thickness tears were arthroscopically debrided. One full-thickness and two partial-thickness tears were repaired using the arthroscopically assisted miniarthrotomy technique. An open repair was performed in two patients. Two isolated rotator cuff contusions were arthroscopically debrided. The average followup was 21 months. Nine of 10 athletes returned to active participation in football, 7 of these at their preinjury levels. The diagnosis of rotator cuff injury should be considered in a contact athlete who has persistent shoulder pain, impingement signs, weakness, and a positive shrug sign. Arthroscopic debridement of the subacromial space followed by debridement or repair of rotator cuff tears, as clinically indicated, resulted in a marked improvement in function and rapid return to sport for these patients.
Subject(s)
Football/injuries , Rotator Cuff Injuries , Shoulder Injuries , Acromion/surgery , Adult , Arthroscopy , Contusions/etiology , Contusions/surgery , Debridement , Endoscopy , Follow-Up Studies , Humans , Male , Microsurgery , Pain/etiology , Pain/physiopathology , Retrospective Studies , Rotator Cuff/physiopathology , Rotator Cuff/surgery , Rupture , Shoulder Joint/physiopathology , Shoulder Joint/surgery , Treatment OutcomeABSTRACT
Out of 78 patients identified who underwent mini-open cuff repair, 64 were interviewed and returned a detailed questionnaire and 47 returned for a physical examination. Their average age was 64 years (31 to 85 years); and the average follow-up was 29.2 months (range, 12 to 65 months). The average tear size was 8 cm2. Preoperatively, all patients complained of pain and weakness. Ninety-six percent of patients displayed positive impingement signs preoperatively compared with 16% postoperatively. Active elevation increased significantly (P < .05) from 129 degrees to 166 degrees. At the time of follow-up there was no significant difference between active elevation in the operative and contralateral shoulders (P > .05). Weakness was detectable by physical examination in 83% of patients initially, and in 22% at the time of the final examination. The average pain and function scores improved significantly. Eighty-nine percent were satisfied with the results of their surgery. Three patients required further surgery on their shoulder. We found no correlation between cuff tear size and final Hospital for Special Surgery shoulder score.
Subject(s)
Arthroscopes , Endoscopes , Rotator Cuff Injuries , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Isometric Contraction/physiology , Male , Middle Aged , Minimally Invasive Surgical Procedures , Pain, Postoperative/etiology , Postoperative Complications/etiology , Range of Motion, Articular/physiology , Rotator Cuff/surgery , Treatment OutcomeABSTRACT
Over 50% of all knee injuries involve partial or complete tear of the anterior cruciate ligament. Surgical reconstruction of this ligament using an isometrically placed bone-patellar tendon-bone autograft is the current technique of choice; however, harvest of patellar tendon as a free graft can lead to increased morbidity. To address this issue, allogenic patellar tendon grafts have been introduced as alternatives to autogenic graft material. The purpose of this study was to examine effects of age and strain rate on tensile strength, modulus, and failure mode of bone-patellar tendon-bone allografts from a typical population of tissue donors. Eighty-two, fresh-frozen, bone-patellar tendon-bone allografts were harvested from 25 different donors, aged 17 to 54. Paired grafts from individual patellar tendons were assigned randomly to tensile testing at either 10% or 100% elongation per second. Tensile strength, modulus, and failure mode were not significantly different for tests conducted at these 2 strain rates. Correlations between tensile strength and age were not significant for tests conducted at either strain rate. Specimens tested at a strain rate of 100% per second exhibited weak but significant negative correlation between modulus and age, with modulus decreasing 25% over the age range examined.
Subject(s)
Aging/physiology , Bone Transplantation/physiology , Patellar Ligament/transplantation , Tissue Donors , Adolescent , Adult , Biomechanical Phenomena , Bone Transplantation/pathology , Elasticity , Female , Fractures, Bone/physiopathology , Humans , Male , Middle Aged , Patellar Ligament/pathology , Patellar Ligament/physiology , Stress, Mechanical , Tensile Strength , Tibia/pathology , Tibia/physiology , Tibia/surgery , Transplantation, HomologousABSTRACT
A prospective study was done of the results of infusion of drained blood after major procedures on the spine and hip in twenty-six patients. The Solcotrans system was used to salvage drained blood in the first six hours after the operation. Transfusion requirements, blood loss, hematocrit, temperature, prothrombin time, partial prothrombin time, platelet count, results of blood cultures, and levels of factor VIII, factor V,D-dimer, antithrombin III, plasminogen, protein C, and complement C3a des arginine were determined for some or all of the patients. A mean of 375 milliliters of blood from the Solcotrans receptacle was reinfused. All of the cultures were negative. There were no febrile reactions. The mean values for the specimens of the salvaged blood were: hematocrit, 0.20; hemoglobin, seventy-one grams per liter; plasma hemoglobin, 2.36 grams per liter; C3a des arginine, 9.4 x 10(-3) grams per liter; fat particles of less than nine micrometers in diameter, 23,643 per milliliter; and D-dimer, 205 x 10(-3) grams per liter. Studies of blood samples that were collected from patients one to two hours and twelve to eighteen hours after the transfusion showed only slight increases in fibrin split products one hour after the transfusion; these values reverted to normal by eighteen hours. No clinical coagulopathy associated with reinfusion was observed. The reinfusion of unwashed, filtered shed blood that was as much as 15 per cent of the total blood volume proved to be a safe technique after major orthopaedic procedures.
Subject(s)
Blood Transfusion, Autologous/methods , Hip/surgery , Spine/surgery , Adolescent , Blood Loss, Surgical , Blood Transfusion , Blood Transfusion, Autologous/instrumentation , Child , Drainage , Equipment Design , Factor V/analysis , Factor VIII/analysis , Female , Hematocrit , Hemoglobins/analysis , Humans , Intraoperative Care , Leukocyte Count , Lipids/blood , Male , Micropore Filters , Platelet Count , Postoperative Complications , Prospective Studies , SafetyABSTRACT
Fifty-eight patients with 62 pathologic fractures secondary to metastatic disease were admitted to a rehabilitation hospital during a 5-year period. Thirty-four patients were discharged home, 7 were transferred to other facilities, and 17 died. The average hospital stay for the patients who went home (37 days) was only 3 days longer than for patients with nonpathologic fractures. No patient could transfer independently or ambulate at the time of admission, but 26 and 23, respectively, could do so by the time of discharge; 27 patients showed significant improvement in their ability to perform activities of daily living as measured by Kenny scores. All 11 patients who had hypercalcemia died. Eleven of 13 patients requiring parenteral narcotics died. Patients with pathologic fractures secondary to metastatic disease are excellent candidates for intensive rehabilitation programs, but hypercalcemia and administration of parenteral narcotics suggest a poor rehabilitation outcome.
Subject(s)
Bone Neoplasms/complications , Fractures, Spontaneous/etiology , Fractures, Spontaneous/rehabilitation , Aged , Aged, 80 and over , Bone Neoplasms/secondary , Female , Humans , Male , Middle Aged , Rehabilitation Centers , Treatment OutcomeABSTRACT
The influence of functional electrical muscle stimulation (FES) on selected properties of vastus lateralis muscle fibres was studied in patients recovering from total knee arthroplasty for osteoarthritis. Prior to surgery, on the average, muscle biopsies from the vastus lateralis could be characterized as having a predominance of Type I fibres which were significantly larger in cross-sectional area than the Type II fibres in the same sample. Following surgery, muscle biopsies from a group of patients (n = 7) which received continuous passive motion and no FES, exhibited a marked increase in the proportion of Type II fibres along with a general atrophy of both the Type I and Type II fibres. Patients receiving passive motion and FES (n = 9) also showed an increase in the relative percentage of Type II fibres. Post-operatively, however, there was no significant reduction in fibre area in the stimulated muscles. These data suggest that FES was effective in attenuating the muscle atrophy associated with total knee arthroplasty but had no influence on those metabolic properties which were related to muscle fibre type classification criteria.
Subject(s)
Electric Stimulation Therapy/standards , Knee Prosthesis/rehabilitation , Motion Therapy, Continuous Passive/standards , Muscular Atrophy/therapy , Postoperative Complications/therapy , Thigh , Aged , Biopsy , Combined Modality Therapy , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Muscular Atrophy/pathology , Muscular Atrophy/prevention & control , Osteoarthritis/surgery , Postoperative Complications/pathology , Postoperative Complications/prevention & controlABSTRACT
The muscle-fiber architecture of 29 muscles from six rabbits (Oryctolagus cuniculus) was measured in order to describe the muscular properties of this cursorial animal, which possesses several specific skeletal adaptations. Several muscles were placed into one of four functional groups: hamstrings, quadriceps, dorsiflexors, or plantarflexors, for statistical comparison of properties between groups. Antagonistic groups (i.e., hamstrings vs. quadriceps or dorsiflexors vs. plantarflexors) demonstrated significant differences in fiber length, fiber length/muscle length ratio, muscle mass, pinnation angle, and number of sarcomeres in series (P less than .02). Discriminant analysis permitted characterization of the "typical" muscle belonging to one of the four groups. The quadriceps were characterized by their large pinnation angles and low fiber length/mass ratios, suggesting a design for force production. Conversely, the hamstrings, with small pinnation angles, appeared to be designed to permit large excursions. Similar differences were observed between plantarflexors and dorsiflexors, which have architectural features that suit them for force production and excursion respectively. Although these differences were not absolute, they represented clear morphological distinctions that have functional consequences.